The invention is based on a plastic articulated arm for a windshield wiper.
Known windshield wipers comprise an articulated arm which is positioned with one end on a wiper shaft driven by a wiper motor. A wiper blade is articulated on its free, outer end. Said wiper blade generally has a multi-member support bracket system comprising a central bracket. Optionally, subordinate brackets are articulated thereto, of which at least several hold a wiper strip with claws at the ends thereof, as well as generally two spring tongues inserted into lateral grooves. Flat-bar wiper blades are also known which, instead of the support bracket system, have a bar-shaped, flexible support element. Said support element is connected via a connecting element to a connection part of an articulated arm in an articulated manner.
The articulated arm of the type to be considered, consists of plastics and has a U-shaped cross-sectional profile with reinforcing ribs which is open toward a vehicle aperture. Additionally, a connection part is formed at the outer end for coupling the wiper blade.
The connection part is inserted from above into a mounting box of the wiper blade, an open hub of the connection part encompassing a pivot pin arranged between the lateral walls of the mounting box, whilst the outer lateral walls of the connection part bear against the internal lateral walls of the mounting box. Thus the pivot pin mounted in the hub forms a joint which permits a pivoting movement between the articulated arm and the wiper blade, whilst the lateral walls of the connection part laterally guide the wiper blade.
Expediently, the articulated arm is produced in its final form in an injection-molding process, so that no subsequent processing is necessary. However, said components have tolerances required by manufacturing. Thus a clearance has to be provided between the rigid lateral walls of the connection part and the lateral walls of the mounting box. Said clearance increases during operation as a result of wear. A lateral clearance between the articulated arm and the wiper blade produces a rattling movement and has a negative effect on the wiping performance. Moreover, undesirable noises are generated as a result of the clearance. Said noises are transmitted undampened via the rigid guide to the articulated arm.
Such articulated arms are, for example, known from JP 2001315622 and JP 2000272478.